Collet chuck



,W. c. HENRY E-l-AL4 COLLET CHUCK Filed oct. 19,4 1943 ocu 23,1945'.

2 SheetS-Shee 1 ALLEN ,MAXA/yf,

' INVEN'lToRs;

ATTORN EY.

o@ z3, 194s. w. C. Hmm En; 2,387,511d

coLLT'HUcK Filed oct. 19. 1943 2 Sheets-Sheet 2 INVENT'oRa Patented Oct. 23, 1945 s PATENT OFFICE e n Wesley Henry, Burbank, and Allen B. Maxam,

. I e Y Glendale, Calif.

` e Application otober 19, 1943, seria1N0.5`06,s00

" s claims.` ',el. 27e- 51) n This invention relates to chucks for lathes and the like and more-particularly to collet chucks. Anobject of the invention is to provide a particularlysimple and positive mechanism for rapidly contracting and expanding a collet chuck andat thesametime exertinga relatively powerful contracting force on the chuck to grip a workpiece therewithin.

Another object is I to provide a' collet chuck structurein which the gripping movement can be quickly and easily adjusted to compensate for variations inthe size of the workpieces and for wear in the mechanism.

"Other objects' and features of the invention g will become apparent from the detailed descriptionto follow of a preferred embodiment of the invention illustrated in the drawings.

Briey, the present invention comprises a collet 'chuck structure adapted` to be used with a conventional lathe having a hollow spindle and consists of a split sleeve adapted to surround the `workpiece and a tapered sleeve concentric with thesplitsleeve' for wedging the -split sleeve about theworkpiece in response to longitudinal move- `ment between the two sleeves. 'Ihe tapered sleeve `is xedwithinithe spindle of thelathe as by having a gradually tapered outer surface adapted to wedge into the conventional tapered bore of the spindle. Longitudinal forceis applied to the split sleeve to force it into the tapered sleeve by a lever and toggle mechanism mounted on a carrler `which is screwed Aon to the `outer threaded surface ofthe lathe spindle. I

This lever and toggle mechanism comprises a plurality lof circumferentially disposed levers on the nose of the assembly, the levers contacting ashoulder on the split sleeve at theirinner ends andbeing movedto exert longitudinal forceon the `split sleeve by a plurality ofutoggles pivotally positioned between the` outer ends of the levers and acollar which is slidable longitudinally and actuated forward and backward by a controlhandle to lock and release the workpiece.

`'Io providefor adjustment of the longitudinal position of the inner ends of the levers-with re-l spectto jthe split' sleeve, the levers are fulorumed on a longitudinally adjustable mounting which is threaded into a separate mounting carrying the actuating collar so.` that, by rotating the le- Inthe drawings:` I

to wedge into a tapered end portion Ill'4 mechanism in accordance `with theinvention; the mechanism being shown mounted on the spindle of a lathe and being shown in closed position n to grip the workpiece;V

` Fig. 2 is a view similar to Fig. 1 but showing the chuck in openposition to release the workpiece; f

Fig. 3 is a cross section taken along the line of Fig. 1;

Fig. 4 is a crosssection takenalong the line Iv--Iv of Fig. 1; e

Fig. 5 is a detail section taken along theline V-V of Fig.2; and y Y Y Fig. 6 is a detail section of a portion of the mechanism of Fig.` 1 showing an adaptation of the invention for mandrel work.

Referring to Figs. 1 and 2, there is shown thel conventional headstock I 0 of va lathe and bearing` I I thereof which rotatablysupports the conventional hollow spindle I2 through which a workpiece I3 is extended and gripped by a collet chuck in accordancewith the invention. This collet chuck comprises a collet sleeve I 4 internally dimensioned to fit and grip the workpiece I3 and having an outer `cylindrical surface I5 which is slidable longitudinally in a cylindrical surface I6 of a supporting sleeve I1, the latter having an outer tapered surface I 8 adapted of the bore of the lathe spindle I2.

The sleeve Il projects forwardly beyond the end 20 of the spindle I2 and is thickened at its outer end to reinforce it. vllt'it's extreme outer end it has a ,taperedl inner surface 2I which ts F1811 is alongitudinal section through a Chuck 55u against a corresponding tapered surface 22 on theendof the collet sleeve I4 so that by forcing the collet'sleeve rearwardly with respect to the supporting sleeve Il, the collet'sleeve is contracted about the workpiece I3 to snugly engage` andA drive it. The collet sleeve is forced rearwardlyV as described by exerting pressure against a shoulder 23 on its forward next to be described.

There is screwed on to the `usual external threads `24 of the'lathe spindle I2 a carrier 25 which supports four levers 26 circumferentiallyarranged around the axis of the' workpiece, a sliding actuating collar 21, anda plurality of toggle links 28, one` associated with. each of theV levers 26. The collar 21 has an annulargroove 2`9` which receives a pair of trunnions 3D on the forked end 3I (Fig. 3) of a handle 32v which is pivotally mounted 'for swinging movement on apost 33 which is securedto the frame ofthe `end by a mechanism When the handle is in one extreme position, the collar 21 is in the forward position shown in Fig. 1 in which the toggle links 28 extend subaway from the shoulder 23 on the colletl sleeve so that it can move forwardly, thereby separating f' the tapered surfaces 2| and 22 on the support-s ing sleeve and the collet sleeve; respectively,` to' release the workpiece.

Considering now the detailed structure of my mechanism, the carrier 25 is formed in two sections 25| and 252, respectively, which are ad justably connected` with each other by screw threads'34 so .that the longitudinal position` .of the -section '252J can .be adjusted by yrotating it with respect to the section 25|, 4and .since the leversl 26 are fulcrumedr to section 252,. their longitudinal vposition is also adjusted` The levers 26 are fulcrumed to the carrier section ..252 -by a row. of `ball bearings 35 .whichft into an internal race in a forwardly extending iiange253 `on the carrier'section. 252 `and exterior races in rearwardly extending ilangesy 26| in the levers 26.- Thus,l referringmtoy Fig. 3, the levers 26 are four in number and each extends substantially over a full.. quadrant so that together the races in the anges 26| of'V the foury levers form an approximately continuous race forV retaining thev balls 35;"

Since Vthe fball races are arcuate', whereas` the levers swing-in radialplanesthe racesare made sufficiently' large -to `permit the desired fulcrurnl action.- However, this fulcrum action Vis not very great since onlyslight movementof the inner ends ofthe levers suices to-engage and disengage the'collet sleevewith the workpiece.

Each lever 26 is`yieldablyurged into disengaged position by a'pair-of helical compression springs-36 which are .positioned in recesses in the forward face of thezlever and cornp1-essedbev tween' the bases'of the recesses and heads 31 of pins extended rearwardly through the lever andY through holes .provided therefor in a radial flange 38'on thev carrier section 252; Thelpins 31 are circurnferentially grooved near their` inner ends and provided with split washers v39 for preventing their withdrawal from the carrier flange- 38.

The outer end of each lever 2li` contacts a central projection 28|'on its associated` toggle link.- 28, the latter being' slightly` lessthan 90 in arcuate :extent asshown-inliig. Ll,l and being recessed at their'innerfedgesrexcept at the ends'where fingers 282 are left tobear against the actuating collar-21.y The inner-.endsfofl the lingers 282 are rounded to t within-.anexternal groove 21| ina forwardly extending flange,212

on the collar 21. Eachfitoggle link 28 is circum frentiallypositioned with `respect to its associated lever '26 by a pin263 ywhich fits in a hole vprovided thereforin the lever and engagesA a longitudinal groove inthe center of the projec-V tion 28|;

As has been previously stated, adjustment of the pressure exertedfby the'levers 26 on the' shoulder 23 -of the collet sleeve can'ibe varied by rotating the carrier section 252 withrespect to the carrier section 25|. This rotation is effectedV is in release position in which it has moved rearwardly against a ilange on the carrier section 25Ij,nand the toggle links 28 have rocked substantially rearwardlyV at their inner ends to permitthesprings y(Mito retract the inner ends of thelevers 26, thereby permitting the collet sleeve |4-tomove`forwardly with respect tothe supporting sleeve I1, the collet sleeve expanding away from the workpiece I3 as it does so, thereby permitting. the workpiece to `be fed or advanced into a new position. Thereafter the handle 32.is ac# tuated toi-shift the collar. 21iinto its; forward position as-shown in Fig. 1 in whichy the-toggle links 28 -eXtend Very.` slightly beyond. a position perpendiculary to the longitudinal axis:Y sothat the. radial `forces applied to. the toggley links 'by the levers retain the collar in position;

It is to Vbe noted .that the only-stop determining the forward movement'of the actuating; collar 21 constitutes the togglevlinks=28themselves which contact the frontV face ofthe collar1'21. 'I'his is advantageous since-it .insuresthat the toggle links :will always stop in :position nearly perpendicular'to the axis of thef-'machinazirrai spective of the adjustmentbetweennthe carrier I section 252 andthe carrier section25|1- There is shown in Fig. 6 a modification of-ithe construction so that the quick* release mechas nism can beusedf with an expansi'ble mandrel for. mandrel workV as well -aswith a contract. able sleeve forcollet work. Parts -in Figrcorre-` spending tothose in Fig 1 bear the'samerefer'.; ence numerals. Itwill be observed thatthevonly changemade is in the-substitution for'the collet sleeve- HI` and the supporting sleeve-I 1 'ofl anna-ns4 drel 50-andfa sleevev 5|.v Themandr'elz 50 takes the placeof the*supporting-,sleevev off'Fig. 1 having :a 'tapered base portion adapted 'to wedge into thetaperedbore -of 'the spindle I2. On. its forward end this mandrel 50 carriesra cylindrial extension 50| f which slidably supports'thefrear portion of the sleeve 5|and has at its'rforw'ard` end atapered portion 502 which` engagesthe corresponding tapered inner surface .5I| fofitlie split end of the sleeve5 I In addition, the sleeve 5| fhas aV fiangef 5|2 which corresponds` in function .to'the shoulder 23 .on the collet'sleeve I4 Tof Fig. l; this shoulder 5|2-:being forced rearwardly by thetipsof the levers126 'when the latter lare actuated'by the collar 2T.V` g 4 As the split sleeve 5 Irides back' on thev mandrel 50, the tapered end 502of the latter expands the outer'end of the 'sleeve 5| tofcause it 4'toene gage the inner bore ofr a workpiece 53 'with whichVA it is to be used.

for fitted to thebore 60 of Athecarrier member 25|, thus permitting the use of alargerkdiameter Collet and accommodating workpieces I3 oisubfstantially the same diameter "as the' diameter of thelathe spindle bore.

inthe appended claims;`

\ We claimz" i l l t 1. In a chuck of the type-described for useA with hollow rotatingdrive spindle; a radially expansible and contractable sleeve member for releasably` gripping aworkpiece; a .cooperating tapered actuating member in 1 concentric relationwith said sleeve member for varying the diameter thereof to cause it to engage the workpiece in response to relativelongitudinal movement between saidfmembers, one of said mem- "bers being adapted to be fixed' to said drive spindleland` theiother member having a shoulder thereon for receiving a longitudinal thrust to move `itilongitudinallywith respect tosaid one member/Gand cause `said sleevermember `to engage the workpiece;` and means for applying thrust to said shoulder, said means. comprising: `a hollow carrier adapted to be secured to said drive spindlein concentric relation with said l members; a plurality of levers fulcrumed on said each `of said levers, each toggle link being pivotally connected to said actuating collar at its inner end and pivotally connected to the associated l lever at its outer end and being movable into substantially radially extending position in response to actuation of said collar in direction to engage said sleeve member with the workpiece.

2. Ina chuck of the type described for use with a hollow rotating drive spindle; a radially expansible and contractable sleeve member for releasably gripping a workpiece; a cooperating tapered actuating member in concentric relation sleeve member with: theworkpiece, the structure for fulcruming said levers on said carrier comprising an annular flange on the end of said -carrier, said ange having a ball race on its inner suface, and said levers having flanges Vcontaining arcuate ball races `juxtaposed to said race in the carrier and a continuous row of balls between said races. i

3. Infa chuck of the type described for use with a hollow rotating drive spindle; a radially expansible and contractable sleeve member for releasably gripping a workpiece; a cooperating tapered actuating member in concentric relation withsaid sleeve member for varying the diameter thereof to cause it to engage the workpiece in response to relative longitudinal movement betweenFsaid members, one of said members being adapted to be iixed to said drive spindle and the other member having a shoulder thereon for receiving a longitudinal thrust to move it longitudinally with respect to said one member and causesaid sleeve member to engage the workpiece; `and means for applying thrust `to said shoulder,` said means comprising: a hollow carrier adapted `to be1 secured `to said drive'spindle in concentric relation with said members;` a plurality of levers fulcrumed on said carrier for movementin radial planes, each lever having an with said sleeve member for varying the diameter i `thereof to cause it to engage the workpiece in response to relative longitudinal movement be- U tween said members, one of said members being adapted to be iixed to said drive spindle and the other member having a shoulder thereon for receiving a longitudinal thrust to move it longitudinally with respect to said one member and cause said sleeve member to engage the workpiece; and means for applying thrust to said shoulder, said means comprising: a hollow carrier adapted to be secured to said drive spindle in concentric relation with said members; a plurality` of levers fulcrumed on said carrier for l movement in radial planes, each lever having an 1 inner end adapted to move against said shoulder outer end and being movable into substantially radiallyextending position in response to actuation of `said collar in direction to engage said inner end adapted to move against said shoulder for applying longitudinal thrust thereto and having an outer end movable with a substantial radial component; an actuating collar longitudinally slidable on said carrier and means for shifting it longitudinally in either direction; and a plurality of toggle links, one for each of said levers, each toggle link being pivotally connected to said actuating collar at its inner end and pivotally connected to the associated lever at its outer end and being movable into substantially radially extending position in response to actuation of said collar in direction to engage said sleeve member with the workpiece, said toggle links each extending arcuately about the axis of said spindle intoclose proximity with the next adjacent toggle links and bearing against said ,actuating collar at their arcutae ends and bearing against the associated levers substantially intermediate their arcuate ends, and means for` preventing arcuate movement of said toggle links with respect to their associated levers.

4. In a `collet chuck for use with a .rotating drive spindle and including a work holding sleeve member contractable about a workpiece in response to inward axial movement of said 'member relative to said spindle, an operating mechanism comprisingza carrier secured to said spindle and surrounding said sleeve member; a plurality of sleeve-engaging levers having inner ends engaging the outer end of said sleeve; means pivotally mounting said ylevers on said carrier for limited substantially axial movement of said inner ends in response to radial movement of said inner ends in response to radial movement of the other ends thereof; an actuating member slidable along said carrier; and a plurality of toggle links, one for each of said levers, each of said links being pivotally connected at the outer end to said other end of the associated lever and having its inner end engaging said actuating member to be moved thereby from an inclined position tc a substantially radial position.

l 5. In a collet chuck for use with a rotating drive spindle and including a work holding sleeve `member contractable about a workpiece in response to inward axial movement of said member@relative1to .said-spindle; anV operatingimech.-v

` mism-comprising; a support secured to saidspin;

die and surrounding; saidsleeveI member; acarrier threadedly securedrto i said-l support `for i axial adjustment s relative lthereto in responsev to rel-1 ative rotation of .said supportand carrier; ,avplurality cf sleeve-engaging levers havingfinner ends engaging the outer end of said sleeve; means pivotally -mountinghA said .levers 'in said carrier for limited. substantially axial movement of` said inner vends in vresponseto:radial movement-,jot the other ends thereof; an I actuating i member slid--A ablealongvsaidoarrier; ay plurality off toggle links, one for eachnof saidnlevers, eachof= said-.links being pivotally connected at the outer endztosaid other end of ysaid associated leverand having-its inner end engagingsaid aetuatingmember/to be moved -thereby from an inclined positionltofa vsubstantially radiall position.wherebytlae` extent of the axial inward movement imparted tosaid Work-holding sleeve may be'adjusted :by relative rotationiof said carrier and said support;v anda spring hdetent deviceF interv-engagingv said-carrier and said'. support Hfor .yieldably yholding saidY carrierH and support vagainstsaidrelativel rotation.

6. Intacollet chuek-forusev` With--a'rotating 'drive -spindleand including aeworkholding; sleeve member contractable about'fa? workpiece-:in .vresponse to inward axialmovement'of .saidlmember relativeftoisaid spindle;A anoperating mechjanisnaV comprising: awcarrier secured tofsaid: spindle'and surrounding said sleeve member; afplurali-ty 0f sleeveengaging levers having inner ends engaging the outer end of said sleeve; means :piv-

v otallyjmountingsaidw'levers and said: carrier for limitedI substantially "axial movement `of said inner ends.l in response to radial movementbf theother ends thereof; an actuating member slidablealongisaid carrier and defining a radialA stop face; apluralityof toggle links, one Vfor-each of isaid levers,` eachwof said links being pivotally connected at the'outer end to said other endhof the associated `lever and having its inner end ,engaging said: actuating` memberv immediately adjacent said'stop face to be-pivotal1y moved from an inclined-positionto a substantially radial position` by slidingvr movement ofV said" actuating member,v ink whichv latter vposition said toggle linksengage said` stopv face and` arrest said slid'- ing movement..v WESLEY C. HENRY, ALLENB. MAXAM. 

